webpack.dev.js

const path = require('path');
const ExtractTextPlugin = require("extract-text-webpack-plugin");
const HtmlWebpackPlugin = require('html-webpack-plugin');

module.exports = {
    mode: 'development',
    entry: {
        index: './src/index.js'
    },
    devServer: {
        port: 8080,
        contentBase: path.join(__dirname, "dist")
    },
    output: {
        path: path.resolve(__dirname, './dist'),
        filename: '[name].bundle.js'
    },
    module: {
        rules: [
            {
                test: /\.js$/,
                exclude: /node_modules/,
                use: {
                    loader: 'babel-loader',
                    options: {
                        presets: ['@babel/preset-env'],
                        plugins: ['@babel/plugin-transform-runtime']
                    }
                },
            },
            {
                test: /\.css$/,
                use: ['style-loader', 'css-loader']
            },
            {
                test: /\.scss$/,
                use: ExtractTextPlugin.extract({
                    fallback: 'style-loader',
                    use: ['css-loader', 'sass-loader']
                })
            },
            {
                test: /\.html$/,
                use: ['html-loader']
            },
            {
                test: /\.(png|jpg|gif)$/,
                use: [{
                    loader: 'file-loader',
                    options: {
                        name: '[name].[ext]',
                        outputPath: 'images/',
                        publicPath: 'images/'
                    }
                }]
            }
        ]
    },
    plugins: [
        new ExtractTextPlugin({
            filename: '[name].bundle.css'
        }),

        new HtmlWebpackPlugin({
            template: 'src/index.html',
            inject: true
        }),
    ]
};